Constructed Resilience. When Adam takes Damage that would reduce him to 0 Hit Points, he must make a Constitution Saving Throw whose DC equals 10 + half the Damage dealt. On a success, he drops to 1 Hit Point instead of falling Unconscious.
Grappler. Adam has Advantage on Attack Rolls made against creatures Grappled by him.
Life Stealer. When Adam deals Damage to another creature using his Bite attack, he regains Hit Points equal to the Damage dealt.
Actions
Multiattack: Adam makes 5 Unarmed Strikes and one Bite.
Bite.Melee Weapon Attack: +10 to hit, reach 5ft., one target. Hit: 40 (6d8 + 10) Piercing Damage. This is a magic weapon attack. Creatures killed by this attack are consumed instead of dropping to 0 Hit Points.
Unarmed Strike.Melee Weapon Attack: + 10 to hit, reach 10ft., one target. Hit: 20 (3d8 + 5) Bludgeoning Damage. This is a magic weapon attack. Each time a creature is hit with this attack, they must succeed on a DC 20 Strength Saving Throw or be Grappled.
Legendary Actions
Adam can take 3 Legendary Actions, using one of the options listed below. He can take only one Legendary Action at a time and only at the end of another creature's turn. Adam regains spent Legendary Actions at the start of his turn.
Bite (2 Actions). Adam takes the Bite Action.
Unarmed Strike. Adam takes the Unarmed Strike Action.
Unarmed Frenzy (2 Actions). Adam lashes out at everything within 10ft. of him. Each creature within range must make a DC 15 Dexterity Saving Throw, taking 10 (1d8 + 5) Bludgeoning Damage on a failed save or half as much Damage on a success.